A common form of liquid dispensing station is a water cooler which dispenses water from an inverted bottle mounted on the water cooler. Water is normally removed from the bottle through a probe which may feed the ambient water to a reservoir provided with a cooling system, so that a supply of chilled water is available from a dispense valve when required.
In order to prevent spillage of water when the bottle is inverted, the bottle is generally provided with a cap which is normally sealed but which is capable of being opened when the inverted bottle is engaged with the probe. It is desirable that the cap is also self-sealing, so that spillages do not occur if the bottle is removed from the water cooler with liquid remaining in the bottle. It is known, for example from U.S. Pat. No. 4,991,635, to provide the cap with a sliding valve element which is held captive within the cap for operation by the probe. In early water coolers the probe only provided a single flow path through which water left the container. Air would periodically return along the same flow path from within the reservoir to replace the water removed from the bottle. The use of a sliding valve element is not detrimental when using such a single flow path, since the air and water travel alternately in pulses and will find their own way past any obstruction which may be presented by the valve components.
It has now become commonplace to provide a second flow path within the probe through which atmospheric air can enter the bottle through a separate vent port at the same time as water is leaving the bottle through the water flow path. This provides a smoother flow, reduces stresses within the bottle, and reduces turbulence within the cooling reservoir which could cause fluctuations in the temperature of the water being dispensed. Hygienic water coolers have a reservoir which is sealed to prevent atmospheric air from entering the reservoir, and clean atmospheric air is drawn directly into the probe without first passing through the reservoir.
In any water cooler having a probe with dual flow paths it is very desirable to prevent air from being entrained into the water which is simultaneously leaving the reservoir. In order to reduce this risk the vent port is positioned away from the water inlet ports.
In the vast majority of water bottles which are supplied at present, the bottle cap is provided with a frangible sealing plug which is broken away from the cap when the probe is inserted. The probe is designed to become frictionally engaged with the plug during insertion so that the plug may re-engage the cap to re-seal the bottle when the bottle is removed. This arrangement has the advantage that the air and water ports of the probe are held clear of the cap so that there is little risk of air entrainment, but there are a number of significant disadvantages. In some cases the plug may float free within the bottle instead of becoming engaged with the probe, which is disconcerting to the user and causes spillage if a partially full bottle is removed. In recent years there has been a trend towards the use of smaller and lighter bottles, which are now commonly thin-walled and moulded of plastics. As the size and weight of the bottle and its contents is reduced the user is often required to apply additional manual downward pressure on the bottle to release the sealing plug. Furthermore, with smaller bottles the insertion distance of the probe becomes more significant, and it is therefore desirable to reduce the penetration of the probe.
A first object of the present invention is to provide a new and inventive form of closure for a liquid container such as a water bottle which requires minimum force to unseal and re-seal the closure when the container is engaged with a probe, which is capable of reduced penetration distance without increasing the risk of air entrainment. An additional first object is to minimise the risk of components becoming free within the container and failing to re-seal when the container is removed.
A second object of the invention is to provide a new and inventive form of liquid dispensing station for use with such liquid containers which provides a smooth flow of air and liquid and contributes towards achieving a reduced penetration distance without increasing the risk of air entrainment.